Extensive scientific research has been directed to back rest design for chairs and car seats with reference to optimizing lumbar support in order to promote comfort and avoid or alleviate backache. While seats with relatively gradually curved cushioned back support in the lumbar area have generally been employed in the manufacture of car seats, limited extra padding for optimum location in the lumbar area has been found helpful to avoid or alleviate backache, particularly in the case of extensive trips where spinal discomfort is frequently encountered.
However, it has proved difficult to standardize the location of any substantial extra lumbar support cushion due to individual size differentials and spinal variations of the occupants. Some prior attempts have been made to meet the requirement for an adjustable lumbar support through the use of Velcro attachments, multiple hook eyelets in the seat back materials, and adjustable strap attachments to the seat back.
The lumbar support of the present invention was developed primarily on the basis of reports in two published articles:
1. SPINE, Vol. 5, No. 2, Mar./Apr. 1980: "Relation Between the Structure of the Annulus Fibrosis and the Function and Failure of the Intervertebral Disc"--Stephen Hickey and David Hukins
2. SPINE, Vol. 4, No. 1, January/February 1979: "The Influence of Backrest Inclination and Lumbar Support on Lumbar Lordosis"--G. Anderson, R. Murphy, R. Ortengren, and A. Nachemson